This invention relates to the field of machines for erecting polygonal paperboard cartons, used for carrying heavy loads, and blanks therefor. Such cartons, and in particular, hexagonal cartons, are well-known. See, for example, U.S. Pat. Nos. 4,166,567, 4,065,047, 3,661,319, 3,526,352, and 3,101,167.
Additionally, a commercially available two-ply carton similar to that shown in U.S. Pat. No. 4,166,567 is known. The commercial carton is manufactured from a collapsed envelope of two paperboard plies, an inner and an outer. Its outer ply has essentially the same construction as that shown in FIG. 3 of the patent. Its inner ply is similar to that shown in FIG. 1 of the patent but it has additional bottom-forming flaps foldably connected to one edge of the inner ply shown in that figure, thus eliminating the need for the bottom insert shown in FIG. 4 of that patent.
The principle disadvantage of the commercial carton is that two people are usually required to set up the carton from the collapsed envelope formed from the two plies. That is due to the large number of panels and flaps that must be folded during erection and the stiffness of the paperboard material. Accordingly, the conventional way of erecting the commercially available hexagonal carton is time-consuming and labor-intensive.